THE DISTRIBUTION PATTERN OF THE SURFACE SEDIMENTS IN THE BERING SEA AND THE WESTERN ARCRIC AND ITS ENVIRONMENTAL IMPLICATIONS

Based on the surface samples collected by the 2^nd-5^thChinese National Arctic Expedition and the V.I.Il'ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, grain size analyses were carried out to define the sediment types and their spatial distribution pattern in order to further probe their environmental implications. The various types of surface sediments are mainly the terrigenous clasts coming from the Arctic and the northwest Pacific, transported by rivers, coastal erosion, ice-rafting, and ocean currents. Most probably due to the different distances from provenance and the different transport medians, the surface sediment types vary from place to place. The grain sizes of the surface sediments decrease gradually with the increase in distance from the land in the north of the Bering sea and the south of Chukchi Sea, and are characterized by poor sorting due to ice-rafting transportation in the high latitude seas.